The overall objectives of the proposed research are to obtain an understanding of the hormonal regulation of spermatogenesis and to clarify the role of Sertoli cells in spermatogenesis. Biochemical techniques will be utilized to obtain information on the biological maturation of the seminiferous tubules and cell culture techniques are being developed to effect these aims. Specific objectives of this proposal are: (a) to characterize primary cultures of Sertoli cells from rats and mice of all ages. (b) to isolate and analyze the secretory proteins of Sertoli cells and to determine the hormonal influences on secretory protein synthesis, (c) to obtain and characterize continuous cell lines of Sertoli cells obtained by transformation and to utilize these cell lines for a genetic and molecular examination of Sertoli cell function.